Patient-reported outcome measures comparing povidone iodine rinse and chlorhexidine rinse for dental implant therapy: a randomized controlled trial

Abstract

Objectives

To evaluate patient-reported outcome measures (PROMs) of povidone-iodine rinse and chlorhexidine rinse for patients undergoing dental implant treatments, as well as their bacteriostatic efficacy.

Materials and methods

Patients needing implant or bone augmentation surgery were randomized into two groups: povidone-iodine(PVP-I) and chlorhexidine(CHX). On the first day after surgery, pain levels were assessed by Numerical Rating Scale (NRS) to compare the two mouthwashes. At two weeks post-surgery, wound healing was evaluated using the early wound healing index. Finally, patient-reported outcome measures (PROMs) were employed to compare each mouthwash’s flavor, texture, and whether it caused irritation or mucosal staining. The significance of intergroup differences was tested using both an intention to treat and a per-protocol analysis.

Results

A total of 83 patients(with a median age of 43, 49 females) were enrolled and randomized. In general, both rinses were similarly favorable in terms of patient comfort. Notably, the postoperative pain NRS was significantly lower in the PVP-I group (1.68 ± 0.82) than in the control group (2.55 ± 1.38, p < 0.01). Regarding to wound healing, there was no significant difference in the Early Healing Index (EHI) between the two groups (Z = 0.351, p = 0.725). Regarding PROMs, at day 7, the swelling reduction was significantly greater in the PVP-I group (p = 0.031). Additionally, fewer participants in the PVP-I group (7%) reported mucosal irritation compared to the CHX group (29%) (p < 0.05), while other PROMs showed no significant differences in both groups.

Conclusions

Within the scope of this trial, PVP-I rinse demonstrated superior patient comfort (significantly lower postoperative pain intensity, less mucosal irritation, and greater swelling reduction at day 7) compared to CHX rinse, though both rinses showed comparable wound healing outcomes. PVP-I may serve as an alternative for dental implant therapy, but all mouthrinses should be used judiciously under clinical guidance.

Trial registration

The study protocol was registered at Chinese Clinical Trial Registry (www.chictr.org.cn) under registration number ChiCTR2500098491 on 10/03/2025 (retrospectively registered).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-025-06560-8.

Introduction

Patient-reported outcome measures (PROMs) are increasingly applied to describe the status and subjective perception of patients after dental treatment. In recent years, it has also gained importance in oral implant treatment [1, 2]. PROMs complement established clinical endpoints in assessing the success of dental treatment, furthermore, postoperative PROMs might reflect the early healing process and inflammatory conditions after dental implant placement.

Infection is a common complication of dental implantation. If not intervened in time, it can affect soft tissue healing, lead to alveolar bone resorption, loosening and detachment of the denture, and result in implant failure [3]. The oral cavity is an environment with a complex microbiological system, and intraoral autotrophic colonisation is the main source of postoperative infections, so postoperative infection control of the oral cavity is crucial [4, 5]. In order to reduce bacterial colonisation, avoid infection and improve implant success, postoperative preventive application of antibacterial rinse has become a standard part of the clinical implant treatment process today. The rinse commonly used today is a 0.12% concentration of chlorhexidine (CHX) solution. Chlorhexidine is a broad-spectrum antimicrobial agent with high sensitivity to Gram-positive and Gram-negative bacteria, which reduces bacterial colonisation and adheres to the surface of the teeth, preventing plaque production [6]. However, long-term use of CHX is prone to staining of the tooth surface and the back of the tongue, taste changes and mucous membrane irritation, and the patient’s perception of its use is not satisfactory [7, 8].

Polyvinylpyrrolidone-iodine (PVP-I) is a complex of polyvinylpyrrolidone and iodine, a broad-spectrum bactericide, stable, odourless, tasteless, and biologically inert and biocompatible. Iodine in PVP-I is found in a variety of forms (e.g. I₂, I⁻, I₃⁻, and PVP-I₃⁻), with free iodine (I₂) as the main bactericidal component. Free iodine (I₂) is the main bactericidal component, which is released continuously from the PVP-iodine complex and thus exerts a killing effect [9]. It is effective against Gram-negative and Gram-positive bacteria, bacterial spores, fungi, protozoa, and several types of viruses [10]. In addition, PVP-I is less toxic and may even have the effect of promoting wound healing [11]. PVP-I is mainly used for the preoperative preparation of skin and open wounds. In dentistry, PVP-I is used as an adjunct to periodontal debridement and helps to reduce the depth of probing [12]. PVP-I solution can also be used as a rinse [13]and its effectiveness as a rinse has previously been verified in clinical trials [14].

Studies related to PROMs for patients using different rinses after implant surgery are currently limited. To investigate whether PVP-I rinse improves patient perception, comparison of patients’ PROMs with PVP-I rinse and CHX rinse respectively, this randomised clinical trial compared the bacteriostatic effect and patient perception of 0.5% PVP-I solution and 0.12% CHX solution as a rinse in implant surgical treatments, with the aim of providing recommendations and evidence for the choice of rinse in implant therapy.

Materials and methods

Eligibility criteria

This trial enrolled patients requiring implant therapy at the Hospital of Stomatology, Wuhan University, during a three-month period (July–September 2023). The inclusion criteria were as follows: patients aged 18–70 years old, needing implantation or bone augmentation, with no contraindications to implant surgery. The exclusion criteria were as follows: patients with iodine allergy, patients who were pregnant or had a plan to prepare for pregnancy in the near future, lactating women, and patients who were not willing to sign the informed consent.

Study design

Subjects all signed informed consent and were randomly divided into test and control groups with equal probability according to a computer-generated random number sequence (Clinical Information Management Suite, Version 5, CMIS-MEDTECH, Chengdu, China). Patients in the test group were given 0.5% PVP-I rinse (Hangzhou Minsheng Pharmaceutical Co.) and patients in the control group were given 0.12% CHX rinse (Shenzhen Nan Yue Pharmaceutical Co.). The implant surgery was performed by the same experienced surgeon, and a nurse was responsible for advising on the use of the rinse and calling back the day after the surgery. At the time of suture removal 10–14 days after surgery, two trained examiners checked the wound healing and oral hygiene of the patients and PROMs were collected from patients by requesting questionnaires to be filled out. Data analyses were performed by a physician who was not informed about the subgroup of subjects. The study protocol was approved by School&Hospital of Stomatology, Wuhan University under the approval number WDKQ2024, and was registered at Chinese Clinical Trial Registry (www.chictr.org.cn) under registration number ChiCTR2500098491. (Fig 1)

Fig. 1.

Consort diagram

Interventions

All subjects underwent necessary periodontal treatment before surgery.

Before implant surgery, subjects were asked to gargle rinse for 1 min to sterilise the mouth. All surgeries were performed by an experienced oral implantology clinician under local anaesthesia (4% articaine hydrochloride with epinephrine 1:100 000). During the postoperative phase, the patients were prescribed oral antibiotics (amoxicillin 500 mg TID or clindamycin 150 mg QID for penicillin-allergic patients) orally or intravenously (if bone augmentation procedures were performed). In addition, post-surgery oral hygiene instructions were delivered, and rinse use was instructed to start 24 h later, using 10 ml each time, gargling and spitting for about 3 min. The timing of use was 10 min after three meals and before bedtime, and no food for 1 h after gargling. The rinse was used for a total of 7 days. Patients were asked to report any adverse events that occurred during the period of rinse use.

Postoperative follow-up included a standardized telephone interview on day 1 to assess pain levels, followed by in-person evaluation during suture removal (days 10–14) to monitor healing and adverse events.

Observation indicators

Numerical rating scale (NRS)

Numerical Rating Scale (NRS) was used to assess the degree of oral pain of the patients in each group on the next day after surgery, with a total of 0–10 points in the scale, with 0 points indicating no pain; 1–3 points indicating mild pain; 4–6 points indicating moderate pain; and 7–10 points indicating severe pain. In this trial, subjects were interviewed by telephone the day after surgery to describe their postoperative pain level on a NRS scale from 1 to 10.

Wound healing status

In this trial, early wound healing index(EHI) is used to evaluate the wound healing status. The degree of wound healing can be categorized into the following grades based on soft tissue conditions such as whether the wound is completely closed or not [15, 16].

(a) EHI 1: complete flap closure-no fibrin line in the interproximal area (2 weeks after surgery). (b) EHI 2: complete flap closure-fine fibrin line in the interproximal area (2 weeks after surgery). (c) EHI 3: complete flap closure-fibrin clot in the interproximal area (1 week after surgery). (d) EHI 4: incomplete flap closure-partial necrosis of the interproximal tissue (1 week after surgery). (e) EHI 5: incomplete flap closure-complete necrosis of the interproximal tissue.

PROMs reported through questionnaires

In addition to standard PROMs assessments, we specifically evaluated mucosal irritation and staining, which were novel endpoints in this trial. The PROMs questionnaire assessed the following parameters using specified scales:

Flavor, smell, perceived effect, and overall comfort: 4-point Likert scale (1 = very dissatisfied, 4 = very satisfied).

Bleeding/swelling severity at day 2 and 7: 4-point severity scale (1 = severe, 4 = none).

Mucosal irritation/staining: Binary outcomes (0 = absent, 1 = present).

Overall comfort: Visual Analog Scale (0-100, higher = better).

All items were assessed during the 2-week follow-up visit.

Data analysis

SPSS (V.25.0) was used for the statistical analysis. The Shapiro-Wilk test was applied to assess the normality of the data. Descriptive analysis for normally distributed data was presented as mean and standard deviation(SD), while for non-normally distributed data, the median was used. For normally distributed data, group comparisons were performed using the independent t-test. Group comparisons for non-normally distributed data and ordinal categorical variables were conducted using the Mann-Whitney test.

Results

Study population

A total of 83 patients met the eligibility criteria, provided consent, were randomized, and received the assigned treatment. Baseline characteristics including implantation sites (categorized by anterior/posterior teeth and maxillary/mandibular jaw), systemic comorbidities potentially affecting wound healing (e.g. diabetes, autoimmune disorders), concomitant medications (e.g. anticoagulants, immunosuppressants), and smoking history (current smoker status and pack-years) were compared between groups using χ² tests or Mann-Whitney U tests as appropriate. No significant intergroup differences existed in baseline characteristics (all p >0.05; Table 1). Specifically, smoking status showed no significant difference in current smokers (PVP-I: 19.5% vs. CHX: 23.8%, p = 0.63) or cumulative tobacco exposure measured in pack-years (median 10.5 vs. 12, p = 0.41).

Table 1.

Patient information

		PVP-I group (n = 41)	CHX group (n = 42)	P value
Age (mean ± SD)		41.20 ± 9.85	44.37 ± 10.63	0.15
Sex, male/female		17/24	17/25	0.94
Implants per patient		1.27	1.36	0.32
Simultaneous bone augmentation (with/without)		27/14	29/13	0.83
		PVP-I group (n = 41)	CHX group (n = 42)	p-value
Implant site
	Anterior/Posterior teeth	15/26 (36.6%/63.4%)	17/25 (40.5%/59.5%)	0.82
	Maxillary/Mandibular jaw	22/19 (53.7%/46.3%)	24/18 (57.1%/42.9%)	0.76
Systemic comorbidities
	Diabetes	3 (7.3%)	5 (11.9%)	0.48
	Autoimmune disorders	2 (4.9%)	1 (2.4%)	0.61
Concomitant medications
	Anticoagulants	4 (9.8%)	3 (7.1%)	0.71
	Immunosuppressants	1 (2.4%)	2 (4.8%)	0.61
Smoking history
	Current smokers	8 (19.5%)	10 (23.8%)	0.63
	Pack-years (median, IQR)	10.5 (5–20)	12 (6–25)	0.41

Primary outcomes

In general, both rinses achieved high patient comfort scores (PVP-I: 92.73 ± 8.89; CHX: 90.81 ± 7.18 on a 0-100 VAS), with no significant difference (p = 0.28). In terms of rinse flavor, effect, comfort, reduction of bleeding and swelling at 7 days and mucosal staining, the results of the PVP-I group were basically not significantly different from those of the CHX group (p > 0.05), except for the reduction of swelling at 7 days, which was significantly better than that of the CHX group (p = 0.031) (Table 2). The incidence of mucosal irritation was significantly lower in the PVP-I group (7%) than in the CHX group (29%) (p = 0.011), indicating that PVP-I caused less mucosal irritation. Similarly, mucosal staining—reported by 24% of CHX users versus only 5% in the PVP-I group (p = 0.013)—further demonstrated PVP-I’s superior biocompatibility profile. This aligns with its minimal tissue-adverse effects observed in wound healing applications (Table 4). The numerical rating scale (NRS) for postoperative pain demonstrated significantly lower scores in the PVP-I group (1.68 ± 0.82) versus the CHX group (2.55 ± 1.38, p < 0.01), suggesting reduced self-reported pain intensity and improved comfort among PVP-I users (Table 3).

Table 2.

Patient-reported outcome measures (PROMs)

	Group	M(P25, P75)	Mann-Whitney U test
			Z	P
Flavor	CHX	3(3, 4)	1.634	0.702
	PVP-I	3(3, 4)
Smell	CHX	3.5(3, 4)	0.325	0.745
	PVP-I	4(3, 4)
Effect	CHX	4(3, 4)	0.901	0.367
	PVP-I	4(3, 4)
Bleeding (day 2)	CHX	3(3, 4)	0.739	0.460
	PVP-I	4(3, 4)
Bleeding (day 7)	CHX	4(3, 4)	1.865	0.063
	PVP-I	4(3, 4)
Swelling (day 2)	CHX	3(3, 4)	1.387	0.165
	PVP-I	4(3, 4)
Swelling (day 7)	CHX	4(3, 4)	2.158	0.031a
	PVP-I	4(3, 4)

^aSignificant difference compared with CHX group

Table 4.

Proportion of participants with mucosal irritation and staining

	mucosal irritation	mucosal staining
CHX group (n = 42)	29%	24%
PVP-I group (n = 41)	7%	5%
P value	0.01a	0.01a

^aSignificant difference compared with CHX group

Table 3.

NRS and comfort

	Group	Mean(SD)	Median	P
NRS	CHX	2.55(1.38)	2	< 0.01a
	PVP-I	1.68(0.82)	1
Comfort	CHX	90.81(7.18)	90	0.28
	PVP-I	92.73(8.89)	95

^aSignificant difference compared with CHX group

Secondary outcome

The Shapiro-Wilk test as well as the histogram results showed that the EHI data of both groups did not obey normal distribution, so the two-sample Mann-Whitney U test was applied. No statistically significant difference was observed in the EHI between the two groups (Z = 0.351, p = 0.725) (Table 5). However, a numerical trend favoring the test group was noted, with marginally higher EHI scores suggesting slightly enhanced early wound healing. This non-significant yet consistent pattern may reflect comparable antimicrobial efficacy between PVP-I and CHX, as both agents appeared to support similar rates of tissue recovery without clinical divergence. Further studies with extended follow-up periods are warranted to explore this observation.

Table 5.

Early healing index (EHI) between the two groups

Group	Median(P25,P75)	Mann-Whitney U test
		Z	P
CHX Group	1(1,2)	0.351	0.725
PVP-I Group	1(1,2)

Implant survival rate

Subjects were followed up for 4 weeks to document implant success. During the trial period, the implant survival rate was 100% in both groups. No allergy and other adverse events were reported.

Discussion

As a common solution for clinical treatment of patients with oral diseases, rinse therapy is a simple method of drug administration, and direct contact with the wound can enhance the effect of the drug, and it can deeply clean the oral cavity, remove residual substances, and improve the oral environment [17]. With the development of medicine, the subjective feelings of patients are increasingly emphasized in addition to achieving objectively good therapeutic results, and thus the concept of PROMs has gained more and more attention in recent years. A systematic review summarized 635 trials that employed PROMs in implant therapy [18]. CHX rinse, which is currently widely used in clinical practice, has reported side effects such as burning sensation and staining of the mucous membranes, however, relevant clinical studies are limited.

This study provides the first direct comparison of patient-centered outcomes between PVP-I and CHX rinses in implant therapy. Consistent with our primary objective, we observed significant differences in PROMs—particularly in pain intensity, mucosal irritation, and swelling reduction—while finding comparable wound healing efficacy between rinses.

The significantly lower NRS pain scores in the PVP-I group (1.68 ± 0.82 vs. 2.55 ± 1.38; p < 0.01) suggest reduced self-reported pain intensity and greater postoperative comfort among PVP-I users. This aligns with Hashemi et al. (2015), who reported fewer analgesic requirements in third molar surgeries with PVP-I. While the mechanism remains unclear, PVP-I’s neutral pH and lack of alcohol may minimize tissue irritation during wound contact. However, as an association observed in this RCT, causality cannot be inferred.

The incidence of mucosal irritation was markedly lower with PVP-I (7% vs. 29%; p = 0.011), indicating PVP-I causes less irritation than CHX—a finding consistent with CHX’s known side-effect profile (Poppolo Deus & Ouanounou, 2022). Similarly, mucosal staining occurred in only 5% of PVP-I users versus 24% with CHX (p = 0.013), reinforcing PVP-I’s biocompatibility advantage in short-term use.

No significant difference in Early Healing Index (EHI) was observed between groups (p = 0.725), suggesting comparable antimicrobial efficacy in supporting early tissue closure. This null result contrasts with Graziani et al. (2024), who reported enhanced healing with CHX in periodontal surgery, but differences in surgical sites (implant vs. periodontal) and rinse concentrations may explain this discrepancy.

However, several limitations warrant acknowledgment. First, short follow-up (4 weeks) precludes assessment of long-term implant success or late-stage complications. Second, subjective PROMs may introduce recall bias, though this was mitigated by standardized collection at suture removal. Third, single-center design limits generalizability; future multi-center trials are needed. Last, bacteriostatic efficacy was not directly quantified (e.g., microbial counts), though EHI indirectly reflects infection control.

Despite these constraints, our use of validated scales (NRS, EHI) and randomization strengthens internal validity.

Conclusion

Within this randomized controlled trial, PVP-I rinse demonstrated significant advantages in patient-centered outcomes compared to CHX rinse for dental implant therapy. Patients using 0.5% PVP-I reported significantly lower postoperative pain intensity (NRS: 1.68 ± 0.82 vs. 2.55 ± 1.38; p < 0.01), less mucosal irritation (7% vs. 29%; p = 0.011), and reduced mucosal staining (5% vs. 24%; p = 0.013), while also achieving greater swelling reduction by day 7 (p = 0.031). Early wound healing outcomes, assessed by the EHI, were comparable between groups (p = 0.725), suggesting similar antimicrobial efficacy in supporting tissue closure.

These findings position PVP-I as a promising alternative to CHX for enhancing postoperative comfort in implant therapy. Future studies should investigate optimal PVP-I concentrations and long-term clinical outcomes to validate its role in routine practice.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Abbreviations

CHX

Chlorhexidine

PVP-I

Povidone iodine

Author contributions

J.C: writing– original draft, investigation, methodology, formal analysis. Z.C: investigation, methodology, formal analysis. Q.Y: investigation, methodology. R.Y: methodology, formal analysis, software. Y.F: conceptualization, project administration, methodology. L.W: conceptualization, funding acquisition, writing– review and editing, methodology. All authors reviewed the manuscript.

Funding

Not applicable.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

The study adhered to the Declaration of Helsinki. The study protocol was approved by Wuhan University School of Stomatology and Wuhan University Stomatological Hospital under the approval number WDKQ2024 and registered with the China Clinical Pathway Registry (www.chictr.org.cn) under the registration number ChiCTR2500098491. Subjects all signed informed consent and were randomly divided into test and control groups with equal probability according to a computer-generated random number.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

CONSORT statement adherence

This randomized controlled trial was designed, conducted, and reported in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines. A completed CONSORT checklist is provided as Supplementary File 1.